<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8"/>
    <meta http-equiv="X-UA-Compatible" content="IE=edge"/>
    <meta name="viewport" content="width=device-width, initial-scale=1.0"/>
    <link rel="stylesheet" href="./css/index.css"/>
    <title>记事本</title>
</head>
<body>

    <!-- 主体区域 -->
    <section id="app">
        <!-- 输入框 -->
        <header class="header">
            <h1>小黑记事本</h1>
            <input placeholder="请输入任务" class="new-todo" v-model="newTodo"/>
            <button class="add" @click="add">添加任务</button>
        </header>
        <!-- 列表区域 -->
        <section class="main">
            <ul class="todo-list">
                <li class="todo" v-for="(item,index) in list" :key="item.id">
                    <div class="view">
                        <span class="index">{{ index + 1 }}</span> <label>{{ item.name }}</label>
                        <button class="destroy" @click="del(item.id)"></button>
                    </div>
                </li>
            </ul>
        </section>
        <!-- 统计和清空 -->
        <footer class="footer" v-show="list.length > 0">
            <!-- 统计 -->
            <span class="todo-count">合 计:<strong> {{ list.length }} </strong></span>
            <!-- 清空 -->
            <button class="clear-completed" @click="delAll">
                清空任务
            </button>
        </footer>
    </section>

    <!-- 底部 -->
    <script src="../../utils/vue.js"></script>
    <script>
        const app = new Vue({
            el: '#app',
            data: {
                list: [
                    {id: 1, name: '跳绳'},
                    {id: 2, name: '游泳'}
                ],
                newTodo: ''
            },
            methods: {
                del(id) {
                    this.list = this.list.filter(item => id !== item.id)
                },
                add() {
                    if (this.newTodo.trim() === '') {
                        alert('请输入任务名称')
                        return
                    }
                    this.list.unshift({
                        id: +new Date(),
                        name: this.newTodo
                    })
                    this.newTodo = ''
                },
                delAll() {
                    this.list = []
                }
            }
        })

    </script>
</body>
</html>
